Nylon is a designation for a family of synthetic polymers known as aliphatic polyamides, and is one of the most commonly used classes of polymers. The chemical constituents of nylon include carbon, hydrogen, nitrogen, and oxygen. Types of nylons include nylon 6,6 that may be formed by reacting the 6-carbon diamine, hexamethylenediamine and the 6-carbon dicarboxylic acid, adipic acid so that amides are formed at both ends of each monomer, nylon 6 that may be made by a ring-opening polymerization of the 6-carbon cyclic amide, caprolactam, and nylon 7 that may be formed by polymerization of either 7-aminoheptanoic acid or enantholactam.
Nylons are designated by a numerical suffix that specifies the numbers of carbons donated by the monomers. For example, for nylons with a two-number designation, such as nylon 6,6 or nylon 6,12, the first number represents the number of carbons from the diamine monomer, and the second number represents the number of carbons from the diacid monomer. For nylons having a single number designation, such as nylon 6 or nylon 7, the number represents the number of carbon atoms in the repeating monomer units.
Nylon 7 is generally an aminocarboxylic acid based nylon fiber having properties that are comparable to or better than those of nylon 6 and nylon 6,6. For example, nylon 7 can provide improved textile properties compared to those of nylon 6 and nylon 6,6. These improved textile properties include higher melting temperature and reduced water absorption. However, there are lacking economically competitive methods for producing the monomers required for the production of nylon 7.
Therefore, there remains a need for methods of producing nylon 7 that are cost competitive with the production methods for producing nylon 6 and nylon 6,6. Methods for producing nylon 7 that are environmentally friendly and recycle waste materials are also desired.